Sleep Apnoea

About one million Australians suffer from sleep apnoea and the condition is often under-diagnosed. CPAP - continuous positive airway pressure - is a treatment for that condition. However, around half of all patients are not able to tolerate it. A recent Australian study analysed the causes of sleep apnoea and looked at alternate therapies.

Transcript

Norman Swan: The trouble with CPAP—continuous positive airway pressure—as a treatment for sleep apnoea is that according to some estimates, around half of people can't tolerate it and either use their CPAP machine irregularly or not at all. This is a huge issue since sleep apnoea is under-diagnosed and affects at least 5% of adult Australians, a number that's growing with the obesity epidemic.

That's led Danny Eckert, a senior research fellow at Neuroscience Research Australia based at the University of New South Wales, to look for treatable factors influencing sleep apnoea in addition to the usual problem of an abnormally narrow and collapsible upper airway. This might suggest alternatives to CPAP. And sure enough, Danny and his colleagues found three such factors.

Danny Eckert: It took us five years to do this study, and it's the most detailed physiological investigation of the causes of sleep apnoea. Really our goal was to bring people into the lab to do detailed physiological measurements over three or four separate nights, so it was really quite an invasive, intensive study.

Norman Swan: So what were the range of causes you discovered?

Danny Eckert: So in addition to that anatomy measure, the collapsibility of the airway, that was one of the more interesting things that we found in this study, that about one-fifth of patients actually had a similar collapsibility or anatomy to the controls.

Norman Swan: So, in other words, the people without sleep apnoea, a very significant percentage of them had this collapsibility but they didn't have any problems.

Danny Eckert: Exactly, and…

Norman Swan: Which means it's dubious, the relationship between that and sleep apnoea in the first instance.

Danny Eckert: What it tells us is that it's one but not the only factor.

Norman Swan: So what's the other stuff?

Danny Eckert: So the other three non-anatomical causes, one was the muscles. So the upper airway is surrounded by over 25 little muscles, and we measured the electrical activity of those muscles during sleep to see how well they opened the airway. The second one was awakening or arousal threshold, as we call it. Some people simply wake up too easily, and that can contribute to their sleep apnoea.

Norman Swan: Well, that sounds counterintuitive, they wake up too easily, you'd think that people with sleep apnoea actually don't wake up and that's the reason they have their problem, their airway collapses before they get into strife.

Danny Eckert: This was one of the new observations from this line of investigation, is that one-third of the sleep apnoea patients in fact wake up too easily to a little bit of a airway narrowing, which we all get, whereas, you're right, on the other extreme there are other patients who really find it difficult to wake up during the night.

Norman Swan: As their partners know.

Danny Eckert: Yes, that's right.

Norman Swan: And what's the consequence of waking up too easily if you've got sleep apnoea?

Danny Eckert: The consequence is that you have a constantly fragmented sleep, so you are awakening repetitively throughout the night, and that obviously disturbs sleep. And the second is if you wake up too easily you are unable to allow your muscles to naturally work to keep the airway open.

Norman Swan: So they don't get a chance?

Danny Eckert: Correct, and there's not enough opportunity to make those muscles work. And the third one is when you wake up from sleep you have a big oscillation in breathing. So you take a big breath, and that blows off your carbon dioxide, and that can set you up for your next event. So they are the three main consequences of waking up too easily that feed into the cycle, that cyclical pattern of sleep disorder breathing.

Norman Swan: So the final one there is it’s not a normal thing, it's an abnormal thing, that because you haven't been breathing properly during the night or since your last wake-up, your carbon dioxide has built up in your bloodstream, you wake up and then you've got to pant a bit to get rid of the carbon dioxide.

Danny Eckert: Exactly, and that was our third trait, which we call respiratory control or…

Norman Swan: Isn't that a good thing?

Danny Eckert: There's obviously a protective role in having some response to an increase in CO2, but what we found in this study was that some people have an overly sensitive response to that carbon dioxide. And for only a little reduction in CO2 they had an enormous breathing response, sometimes five, six, seven, eight, nine times bigger than they should.

Norman Swan: So, in other words, their sleep apnoea might be, to somebody observing it, exaggerated. It might not be as bad as it sounds because they are taking a huge gulp of breath when they might not need to.

Danny Eckert: That's exactly right. And then, again, because of those changes in carbon dioxide, that sets them up for the next breathing event.

Norman Swan: So what's the cart and what's the horse? Because you could have this abnormality in your throat, then you progress into your muscles not working very well and you progress into this waking up and then you progress into this big gulp of air, and it's all started from the anatomical abnormality because your neck is not right. Or it could all happen together. Could it ever be that the big gulp of air is your problem and then that leads to sleep apnoea?

Danny Eckert: No, I think fundamentally you have to have some degree of anatomical compromise to have sleep apnoea.

Norman Swan: So let's take an analogy, which is incontinence. Men suffer from incontinence as they get older, and it's not just their prostate, and it's the same reason why women tend to get more incontinence as they get older, their muscles don't work as well. The link between the brain and the muscles in the bladder and the sphincter don't work as well, and you tend to have incontinence, and you tend to blame it on other things, like you've got prolapse or you've got a prostate, but in fact it's just the ageing process. So let's just take the muscle bit. To what extent is the muscle problem in sleep apnoea just an ageing phenomenon that the brain is not connecting to the muscles that well anymore, just because you are 75?

Danny Eckert: Yes, if you combine some anatomical compromise with that muscle factor that you talked about, they are two factors that can set you up for sleep apnoea. And you're right, maybe that is why some people get sleep apnoea, because ageing is certainly one of the biggest risk factors for sleep apnoea. And there have been small mechanistic studies to show that the reflexes that keep the airway open are impaired with ageing, and also some evidence to suggest that the muscles may not respond as well. So that could well be a factor.

Norman Swan: And of the people that you studied with sleep apnoea, how many had the full house; the anatomical abnormality, the problem in their muscles, the gulp of air, and waking up frequently? In other words, did you have to have a full house, or you could have only some of them?

Danny Eckert: That was really the main finding of the study, was that there were many different reasons on a per patient basis. So you're right, there were some people who were extremely severe, they had terrible anatomy, they had bad loop gain, as we call it, or respiratory control, bad muscles and bad awakening responses. They were relatively a minority. What we found is that one-fifth of patients had the same measurable anatomy or collapsibility of the airway as many of the controls, but those individuals had one or more non-anatomical causes, whereas the controls did not. So they were protected.

Norman Swan: And did these other causes predict lack of ability to tolerate CPAP?

Danny Eckert: It's a really important question and one that we have not yet answered.

Norman Swan: So given that you found people who had collapsible airwaves but no sleep apnoea, that assumes, maybe, that if you got rid of the other causes you could actually do something about the sleep apnoea. What treatments might be available to fix up the muscles, to fix up the sleep awakening, to fix up the big gulp of air?

Danny Eckert: This is really one of the biggest things that came out of this detailed study, was that these data suggest that over 50% of patients could potentially be treated without CPAP therapy if you target one or more of the abnormal traits with a combination of approaches. Those approaches are…this is all at the early stages, but for example to reduce respiratory control you can give oxygen therapy or another drug called acetazolamide can stabilise those unstable…

Norman Swan: Swings in carbon dioxide and so on.

Danny Eckert: Correct. So that's one approach, to target that particular mechanism. The overly sensitive awakening, or what we call a low arousal threshold, we are now doing detailed studies at NeuRA to investigate what certain sedatives or sleeping pills can affect or dampen down that response to stabilise breathing in those individuals. It is actually quite a counterintuitive…

Norman Swan: That's the thing, you wouldn't want to take a sedative if you've got sleep apnoea because it could make you worse. But maybe, carefully done with a certain type of one, it could work.

Danny Eckert: I think that's a really exciting area of investigation. Obviously you need…some of the older drugs, benzodiazepine, that will potentially relax the muscles are not going to work…

Norman Swan: So this is not something to try at home by yourself.

Danny Eckert: Very clearly not, and because there are certain patients that will get worse if you give them a sedative. So our approach, using this framework, is to find the ones that we think are going to get better and to deliver some of these novel therapies.

Norman Swan: And is there a way of exercising the muscles?

Danny Eckert: There are, there's been some interesting studies over the years that training may help, so somewhat surprisingly a study of the didgeridoo out of Switzerland showed that there was some improvement in sleep apnoea severity, published in the British Medical Journal.

Norman Swan: So didge therapy?

Danny Eckert: That's right. And look, there are novel devices too, some implantable devices that stimulate the nerve to the largest upper airway dilator muscle, genioglossus, that are currently under trial at the moment that may have some benefit in the appropriately selected individuals. And again, in addition to…there's also been a trial out of Brazil to show that if you get a speech pathologist to use certain training exercises, that can also have an effect in reducing sleep apnoea severity.

Norman Swan: By training the vocal muscles?

Danny Eckert: Yes, and potentially there are, again, avenues for novel therapeutics to stimulate these muscles, but that area is really quite a long way off.

Norman Swan: So do singers get less sleep apnoea?

Danny Eckert: Look, it's an interesting question, and there is very little published data on that question, but it's unclear at this stage, but worthy of investigation.

Norman Swan: Can the system afford to do all the testing that's required to pick up these extra abnormalities? Because this is expensive stuff; you've got to go into a sleep lab, you've got to be attached to all sorts of wires. This sounds like very expensive interventions.

Danny Eckert: What we've done here is do the baseline detailed physiology study to set the framework. As you rightly point out, we need to get simplified measures in order to deliver individualised therapy for sleep apnoea, and we have made some initial progress in that area where we can get these measurements on a single overnight study rather than doing three or four with detailed measurements.

Norman Swan: Danny Eckert, thanks for joining us on the Health Report.

Danny Eckert: Thank you.

Norman Swan: Danny Eckert who is a senior research fellow at Neuroscience Research Australia which is based at the University of New South Wales.

I'm Norman Swan, and you've been listening to the Health Report. I'll see you next time.

Guests

Dr Danny Eckert

Senior Research FellowNeuroscience Research AustraliaUniversity of New South WalesSydney

Further Information

Credits

Comments (10)

Jon Danzig :

15 Oct 2013 3:14:38am

I now won't sleep without my CPAP machine that for me is 100% effective at resolving both snoring and sleep apnoea. I’m grateful to the Australian physician, Dr Colin Sullivan, who invented this device.

However, here in the UK, my journey to being diagnosed was bizarre. I’ve just published a blog about my overnight sleep test at an exclusive London hospital, usually frequented by the Royal Family. It was a comical disaster and I didn't sleep a wink all night. Hopefully overnight sleep tests in Australia are less eventful.

Dr Tad Soroczynski (PhD) :

16 Oct 2013 5:57:37pm

Thank you for presenting this report. I wish to share my experience in this area. I have been suffering from sleep apnoea since 2004, CPAP machine have not been working for me so I have undertaken my own research.

In my opinion, most currently available devices for controlling sleep apnoea do not deal with the problem of efficient breathing. Efficiency of human breathing and the benefits of nose breathing on human health have not been considered or evaluated.

I have developed a new mask which seals the mouth and promotes natural breathing through the nose, which is the most healthy and effective method of breathing. I have been using natural breathing mask to control my sleep apnoea since September 1, 2012.

On the basis of my personal experience, the performance of the nose-breathing mask is summarised as follows:

• I have been breathing with my whole lungs for the first time in my life. I remember that at the age of 17 I could not finish a 1500 m race, as I was unable to breath properly. • I have been getting up refreshed and I am not sleepy till 10:00 am as formerly.• I have not been experiencing dry mouth and throat.• I have not been experiencing dry nose.• I have been experiencing clear thinking.• I have been snoring slightly when I have been sleeping on my back, so I have been avoiding such position. • Recently, I drove a car for 250 km (this was my first driving test) without any problem. Before I couldn’t see the road after driving 100-150 Km, I had to stop and rest for 20-30 minutes.• I have also observed that, after rising at night, and later sleeping without mask I have been sleeping with mouth closed. In this situation, I have observed that I have been breathing through my nose. This means that it may be possible to retrain the brain for proper nose breathing. It is considered that this issue requires more research.

In conclusion, the performance of mask has exceeded expectations as I have been cured from sleep apnoea and have improved my breathing performance.

Dr Tad Soroczynski (PhD) :

16 Oct 2013 8:42:11pm

I wish to offer my additional comments. On the basis of my personal experience sleep apnoea should be considered as a breathing disorder. As natural breathing through the nose is the most beneficial for the human health, therefore, breathing through the mouth needs to be considered and treated as a disorder.I have improved my breathing and as a consequence all symptoms of sleep apnoea have been almost eliminated.I wish to suggest that the above experience needs further consideration and examination.

Paul O'Connell :

17 Oct 2013 9:38:19pm

I learnt Buteyko Breathing in 1994 and overcame lifelong asthma, coming off all medication. I then trained as a Buteyko Practitioner, including training with Professor Buteyko from Russia. Three years later I quit my corporate career and began teaching Buteyko Breathing courses full time in Australia and around the world. I have taught Buteyko Breathing courses to over 8,000 people with breathing disorders, particularly sleep apnoea, over the last 19 years. Sleep apnoea is a breathing disorder and is reversed by learning to breathe correctly with the Buteyko Breathing Method. CPAP and splints are symptomatic treatments which do not address the underlying cause - incorrect breathing. I suspect most people would prefer to attend a Buteyko Breathing course than to learn to play a Didgeridoo.

S.Strobel :

18 Oct 2013 10:51:18pm

One cause not mentioned at all is 'lifestyle'; I read decades ago that rich late night dinners combined with an over abundance of alcoholic beverages can lead to sleep apnoea; and a personal study of my then middle-aged sleeping partner gave me ample evidence of the above!

Michael Lingard :

20 Oct 2013 10:57:44pm

You are right (Strobel)the heavy late meal and alcohol both further disturb the breathing and will possibly tip a dysfunctional breather into sleep apnoea episodes. Once again returning to perhaps the main underlying cause, dysfunctional breathing. It is exactly this as Paul O'Connell says, that gives long lasting results in the vast majority of cases. ( A conclusion based on a recent study of 11,000 patients with sleep apnoea)

Steve Lumsdaine :

21 Oct 2013 2:42:22am

I understand that in 5 years of investigation Dr Eckhert may have looked at factors other than those mentions in the interview.

In my experience, the 3 factors which are most critical are:1) Minute volume of air being breathed between apnoeas. (And correspondingly, when awake.) Chronic hyperventilation may cause snoring and apnoea.2) Sleep position - on the back is generally much worse.3) Locus of breathing - nasal diaphragmatic breathing is best.

There was also no mention of centrally mediated apnoea - just obstructive.

The term "sleep disordered breathing" was used in the interview. It may be more useful to think of "breathing disordered sleep" and to investigate the possibility that apnoea may simply be a defence against hyperventilation. Too simple?

steve Haggie :

21 Oct 2013 12:08:18pm

i recently attended Buteyko clinic in Auckland because of my severe sleep apnea.After 3 days of a five day course and understanding why i was so bad ,and that by controlling my breathing thru my nose at all times,night and day i am now cured.No longer is my wife laying awake at night time waiting for me to hold my breath then shake me awake to start breathing ,she is now for the first time in many years getting a full nights sleep.By sleeping on my side ,breathing thru my nose i now sleep so well and wake up refreshed.

Bob Elliston :

21 Oct 2013 10:51:02am

Dear Health Report,I have observed numerous pieces of anecdotal evidence to suggest that the current “normal” values for Thyroxine in the blood are deceptively low at the low end of the range. Many people appear to be walking around with untreated, borderline HypOthyroidism. They all tend to have obesity, lethargy, snoring and sleep apnoea. I know of two actual concrete cases where sleep apnoea has been cured (as a side effect) by treatment with Thyroxine. They are my mother and my girlfriend so observations didn’t require a laboratory. I have wondered if obesity, and sleep apnoea in particular, would be treated more easily with the assistance of Thyroxine at high doses, just short of causing any serious symptoms of HypERthyroidism, such as cardiac arrhythmias. The added muscle tone and reduced fat in the tissues would both tend to open airways in a more acceptable way than by using CPAP machines. Please, can someone do some research on this?

Tad Soroczynski :

I regret that I was not taught proper breathing when young, as were the young children in Glasgow, see: http://www.buteykoairways.com.au/documents/Buteyko_Glasgow_Schools.pdf

As a young man, I experienced breathing problems, and later in my life I suffered from sleep apnoea. These problems lasted for more than 60 years, and I am now almost 80 years old.

On the basis of my experience, any improvement in breathing efficiency may be related to the following: i) the adoption of a proper breathing pattern, ii) the adoption of increased breathing efficiency, and iii) the development of a habit of good breathing which would then permit one to breathe properly at night, (this issue is, currently, a challenge for me).

If, when young, I had been taught to breathe properly, my life would, probably, have been different. It is, therefore, my opinion that an explanation of the benefits of proper breathing should be taught in all our schools.